この規格は，主として自動車に使用する冷間圧造成形の，六角穴付きボルト（以下ボルトという。）について規定する。

注記 このボルトは，頭部をざぐり穴の中に埋め込む部位など，頭部周辺が狭く外側駆動の六角頭が使えな い場合に用いる。ISD フランジ付き六角ボルトよりも座面積が３割から６割小さく，強度区分に見合った 軸力の確保が困難なため，標準ボルトとしての使用を順次制限し，特殊用途用として図面での運用に 移行していく予定である。

This standard covers the cold-forged steel hexagon-socket-head bolts, mainly used in automobiles (hereinafter referred to as "bolts").

Note: The bolts of this standard are used where space restriction around the hexagon head refuses the tool access to the heads for driving them, such as in the case of sinking a hex head into a spot faced recess. The bolts of this standard are smaller in the bearing surface area than their corresponding hexagon head bolts by 30 to 60%, making it difficult to secure axial tension appropriate for their property class; therefore, they will be gradually restricted in use as standard parts and will be used as the parts for special uses, for which drawings are issued.